Wood on the menu

Today, Doc was weeding a patch of ground near the bank of rhododendrons and he inadvertently disturbed a wasp nest.  He was irritated at finding yet another nest but not as irritated as the wasps who were trying to finish building it.  No sooner had Doc found the nest than I heard those familiar nibbling noises whilst I was filling a watering can from the water butt next to the greenhouse.  

We first came across this garden phenomen a couple of years ago and then, the idea of wasps munching our greenhouse was amusing. We also thought that it is important to see wasps as a vital part of the garden's natural balance because they devour pests such as aphids and caterpillars.   However, we now have an awful lot of furry vertical lines etched into the wooden window frames and their munching is extremely annoying.  Shooing them away is useless because they return a minute or so later, usually with reinforcements.  Once they sink their mandibles into the wood, there seems to be no stopping them. 

Although our greenhouse is large we don’t like the wasps free loading at our expense.  One of these days we will walk down the garden and instead of seeing an abundant greenhouse full of tomatoes and peppers we will see a pile of sawdust and broken glass. The cost of replacing the greenhouse would be considerable but our tenderly nurtured vegetables are priceless.

Apparently, this problem is unusual but not unheard of and occurs mostly where there is a high wasp population such as in orchards.  The wasps look for wood which they chew into paper and use it to build or repair their nest.  They will consume trellis panels, wood planters, sheds, fences, decking and furniture - and of course greenhouses.  Cedar is particularly delicious because the natural oil in the wood has an attractive smell which makes me think that we should have bought an aluminium greenhouse.  I seem to remember that it would have been a lot cheaper... 

There are products which can be painted on the wood at the start of the season – when the little blighters are most active - and these contain repellents such as eucalyptus oil, menthol and citronella.  However, this is impractical for larger areas and I am told that the best solution is to find and eradicate the nest - or nests. 

So, actually, Doc has done us a favour in finding this new nest.  He has now written ‘evict wasps’ on the Garden To Do list.  In the meantime, I have installed the temporary deterrent.  I hang a jar of water by the water butt, containing a dollop of my very best raspberry jam.  There are a dozen or so wasps in there already.  And when I shut the greenhouse door, I will do so very carefully, just in case it is about to fall down.